Ductile fracture prediction in thin-walled structures through a novel damage model

Area of Science:

• Materials Science
• Mechanical Engineering
• Computational Mechanics

Background:

• Accurate prediction of ductile fractures in thin-walled structures is crucial for safety in automotive, marine, and aerospace applications.
• Existing damage models face challenges in predicting fractures across diverse strain localization conditions, from biaxial compression to tension.

Purpose of the Study:

• To develop and validate a specialized damage model for shell elements to enhance ductile fracture prediction accuracy.
• To improve the prediction of failure displacement under shear stress and regularize the fracture locus across various loading conditions.

Main Methods:

• Utilized experimental data from shear, uniaxial, and plane tension tests to develop a specialized damage model for shell elements.
• Employed ratios of necking to failure displacements from tension tests to regularize the fracture locus for 3.0 mm shell elements.
• Compared the proposed model's performance against the Walters model using simulated three-point bending tests.

Main Results:

• Achieved a 50% improvement in failure displacement prediction under shear stress compared to digital image correlation.
• Successfully regularized the fracture locus for shell elements, covering the range from biaxial compression to tension.
• Demonstrated enhanced accuracy in predicting the occurrence, shape, and force-displacement characteristics of ductile fractures.

Conclusions:

• The proposed damage model offers superior accuracy for predicting ductile fractures in shell elements compared to existing models like the Walters model.
• This advancement is expected to significantly improve the precision of ductile fracture predictions in practical engineering applications.
• The model's ability to handle diverse strain localization conditions marks a significant step forward in structural integrity analysis.